1. Field of the Invention
The present invention is concerned with a novel process for the manufacture of quinone derivatives, especially of compounds of the vitamin K series and of ubiquinones. The invention is also concerned with novel starting materials and intermediates in this process.
2. Description
The hitherto known processes for the manufacture of such compounds normally start from hydroquinones or monoacylated hydroquinones and are therefore technically unsatisfactory, since a relatively large number of reaction steps must be carried out. Technically practicable processes starting from, for example, menadione itself or a readily accessible derivative thereof are hitherto unknown. This gap has now been closed by means of the process in accordance with the invention, since this permits vitamins of the K series as well as ubiquinones to be manufactured in one or two steps starting from readily accessible starting materials. Moreover, the process in accordance with the invention is of particular interest, since, in contrast to many previously known processes, it terminates with practically complete retention of the configuration of the double bond(s) in the side-chain.